1. Field of the Invention
The present invention relates to a printed circuit board assembly that contains a heatpipe.
2. Description of Related Art
Integrated circuits are typically assembled into packages that are mounted to a printed circuit board(s). The integrated circuits generate heat which must be removed from the package. Some packages incorporate heat slugs and/or heat sinks to increase the heat transfer rate between the integrated circuit and the surrounding ambient air.
There have been developed integrated circuit packages which generate a relatively large amount of heat. For example, there have been developed multi-chip modules (MCM) which contain a number of individual integrated circuits. The heat generated by some MCMs require a cooling system that is more efficient than conventional heat sinks and heat slugs.
There have been developed computer products which utilize heat pipes to remove heat generated by integrated circuits. Heatpipes contain an internal fluid that transfers and removes the heat from the integrated circuit packages. The fluid is evaporated at one end of the heatpipe and then condensed at an opposite end of the pipe. The evaporation process pumps the fluid to the condensor portion of the heatpipe. The heatpipe also contains an internal wick that allows the condensed fluid to be drawn back to the evaporation portion of the pipe to complete the cycle.
The heatpipes are typically mounted to the printed circuit board assembly with a contact plate. The contact plate is machined from a metal material. Machining metal is a relatively expensive manufacturing process. Additionally, the metal material increases the weight of the system. It would therefore be desirable to provide a means for coupling a heatpipe to a computer assembly that is inexpensive and lightweight.
The tubular wall of a heatpipe is relatively thin to minimize the thermal impedance of the pipe. Unfortunately, the thin wall does not provide a large amount of stiffness. It has been found that heatpipes may bend and warp when subjected to the thermal cycling of a computer. The warping may create voids and spaces between the heatpipe and the integrated circuit package. The spaces increase the thermal resistance of the assembly and the junction temperature of the integrated circuits. It would therefore be desirable to provide a heatpipe assembly that is lightweight, inexpensive and structurally rigged enough to prevent warping of the pipe.